While used to identify points or small features at the surface, XPS can also be used to image the surface of a sample. This is useful in understanding at the distribution of chemistries across a surface, for finding the limits of contamination, or even examining the thickness variation of an ultra-thin coating. There are two approaches for obtaining XPS images: mapping (serial acquisition) or parallel imaging (parallel acquisition). In this section we will describe how both of these approaches work, and the benefits of each approach.
Mapping (Serial Acquisition)
Serial acquisition of images is based on a two-dimensional, rectangular array of small-area XPS analyses. This method enables measurements of the distribution of elements or chemical states. The ultimate spatial resolution in the image is determined by the size of the smallest analysis area, which is approximately 15 μm for all Thermo Scientific XPS Instruments. Serial acquisition is generally slower than parallel acquisition but can collect a range of energies at each pixel compared with collecting only a single energy for parallel acquisition.
Used in combination with a multi-channel detector, serial acquisition of maps can result in ‘snapshot’ spectra being produced at each pixel. The Thermo Scientific K-Alpha and Theta Probe XPS Instruments can scan the sample stage to obtain images. Using this method, the analysis position is fixed and the specimen surface is moved with respect to this position.
Advantages of mapping:
Parallel Imaging
Instrument components necessary for parallel acquisition of photoelectron images using the Thermo Scientific ESCALAB Xi+ XPS Instrument.
Xps Mapping Vs Imaging System
Parallel acquisition of photoelectron images is easily achieved using the Thermo Scientific ESCALAB Xi+ Instrument. This method simultaneously images the entire field of view without scanning voltages applied to any spectrometer component. For parallel acquisition, additional lenses equipped with a two-dimensional detector are required. The photoelectrons pass through lenses 1 and 2 in the transfer lens assembly, producing a photoelectron image of the specimen surface at some plane within the lens column after each lens (the image planes). Lens 3 is operated such that its focal length is equal to the distance between the lens and the second image plane. Therefore, electrons emanating from any point on the image will leave lens 3 on parallel paths. The angle between the beam of electrons and the lens axis will depend on their distance from the lens axis in the image plane. The electrons then enter the analyzer, which functions as both an energy filter and a lens. If the analyzer’s deflection angle is 180°, then the angular distribution of the electrons is retained as they leave the analyzer. A fourth lens (lens 4) operated in the reverse manner of lens 3 will reconstruct the image at a two-dimensional detector placed at the focal length of lens 4. The electrons forming the image have passed through the energy analyzer and by tuning the analyzer to the energy of a photoelectron peak, a chemical image is constructed.
Parallel XPS image from a Cu grid using monochromated Al K-alpha X-rays and theThermo Scientific ESCALAB Xi+ XPS Instrument.
The spatial resolution of parallel imaging depends on the spherical aberrations in the lens. Limiting the angular acceptance of the lens can reduce the effect of the aberrations, which improves resolution at the expense of sensitivity. The use of a magnetic immersion lens in the specimen region also reduces aberrations, producing higher sensitivity at a given resolution. This method of imaging is fast and produces the best possible imaging resolution.
Parallel Imaging provides the best resolution and is faster than serial methods for producing an image at a single energy. Spectroscopy from images is possible by collecting a series of images at different energies across each peak required, effectively running a scanned XPS acquisition for each pixel in the image.
What is the difference between multispectral and hyperspectral imagery?
Multispectral vs hyperspectral. What are the differences between the two?
When you read this post, your eyes see the reflected energy. But a computer sees it in three channels: red, green and blue.
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Now, imagine if we could view the world in the eyes of a human, goldfish and bumble bee? Actually, we can. We do this with multispectral and hyperspectral sensors.
The Electromagnetic Spectrum
Visible (red, green and blue), infrared and ultraviolet are descriptive regions in the electromagnetic spectrum. We, humans made up these regions for our own purpose – to conveniently classify them. Each region is categorized based on its frequency (v).
Multispectral and hyperspectral imagery gives the power to see as humans (red, green and blue), goldfish (infrared) and bumble bees (ultraviolet). Actually, we can see even more than this as reflected EM radiation to the sensor.
The main difference between multispectral and hyperspectral is the number of bands and how narrow the bands are.
Multispectral imagery generally refers to 3 to 10 bands. To be clear, each band is obtained using a remote sensing radiometer.
Hyperspectral imagery consists of much narrower bands (10-20 nm). A hyperspectral image could have hundreds or thousands of bands. In general, it comes from an imaging spectrometer.
Multispectral Imagery Example
An example of a multispectral sensor is Landsat-8. Landsat-8 produces 11 images with the following bands:
Each band has a spatial resolution of 30 meters with the exception of band 8, 10 and 11. While band 8 has a spatial resolution of 15 meters, band 10 and 11 have 100 meter pixel size.
If you’re wondering why there is no 0.88-1.36 band, atmospheric absorption is the main motive why there are no sensors detecting these wavelengths.
Hyperspectral Imagery Example
The TRW Lewis satellite was meant to be the first hyperspectral satellite system in 1997. Unfortunately, NASA lost contact with it.
But later NASA did have a successful launch mission. The Hyperion imaging spectrometer (part of the EO-1 satellite) is an example of a hyperspectral sensor. For instance, Hyperion produces 30-meter resolution images in 220 spectral bands (0.4-2.5 um).
NASA’s Airborne Visible / Infrared Imaging Spectrometer (AVIRIS) is an example of a hyperspectral airborne sensor. For example, AVIRIS delivers 224 contiguous channels with wavelengths from 0.4-2.5 um.
Multispectral vs hyperspectral
Multispectral vs Hyperspectral
Having a higher level of spectral detail in hyperspectral images gives better capability to see the unseen. For example, hyperspectral remote sensing distiguished between 3 minerals because of its high spectral resolution. But the multispectral Landsat Thematic Mapper could not distinguish between the 3 minerals.
But one of the downfalls is that it adds a level of complexity. Ami misir ali pdf download. If you have 200 narrow bands to work with, how can you reduce redundancy between channels?
Hyperspectral and multispectral images have many real world applications. For example, hyperspectral imagery has been used to map invasive species and help in mineral exploration.
There are hundreds more applications where multispectral and hyperspectral enable us to understand the world. For example, we use it in the fields of agriculture, ecology, oil and gas, oceanography and atmospheric studies.
What if you took one of the best-looking, most capable 13-inch Windows laptops and added a 360-degree hinge that let you fold back the screen into a makeshift tablet? Make it thinner and lighter, and keep the entry price just under the $1,000 mark and you'd really have something.
That perfectly describes the new Dell XPS 13 2-in-1.
The original XPS 13, which dates back to 2015, delivered a striking design that stretched the laptop display from one edge of the lid to the other, reducing the bezel (that black strip around the screen) to a bare minimum. Now, as the thinner and lighter laptop design andno-bezel look has become a bit more of a commodity, Dell has upped the ante, allowing this touchscreen laptop to transform into a tablet.
I'd call the new 2-in-1 version of the XPS 13 a full-time laptop and part-time tablet, as opposed to something like the Microsoft Surface Pro, which is a full-time tablet and -- with the addition of its optional snap-on keyboard -- part-time laptop. And even if you never fold the XPS 13 2-in-1 back into a tablet, it still works perfectly well as a clamshell laptop.
The overall design is close to my platonic ideal of a modern laptop. It's slim, there's little wasted space on the compact body, and it has a few high-end features that help it stand out, such as a fingerprint reader, Thunderbolt-enabled USB-C ports, a dual-lens IR webcam, and that great edge-to-edge display. Note that the fingerprint reader works for Windows Hello login right now, but support for facial recognition login from the camera is coming via a future software update.
It benefits greatly from a comparison to the standard XPS 13 model, which Dell still sells (see our most recent review here). The 2-in-1 version is thinner and doesn't have the wedge shape that made the standard XPS 13 feel a bit bulky, but still has the same excellent keyboard and large touch pad. The configuration of the XPS 13 2-in-1 tested here is $1,299 in the US, but it starts at $999 for a decent set of components and the same 1,920x1,080 touch screen as this one.
This should be your default choice for an XPS laptop right now, even over the standard clamshell version, although it's worth noting the non-hybrid XPS 13 pulls its processors from a faster selection of CPUs. It's also a strong competitor with other premium hybrids, such as the Acer Spin 7.
Available configurations in the UK and Australia vary a bit from the US ones, with starting prices of £1,349 and AU$2,299, making it less of a midprice system in those territories.
Xps Mapping Vs Imaging CenterXps Mapping Vs Imaging PrinterA tale of two chips
There are a few sacrifices to make. The most important is swapping a standard Intel Core i3 or i5 U-series CPU for a lower-power Y-series one. That's basically a rebranded version of what Intel previously called the Core M CPU, which isn't as fast, but does work better in slim PCs that need to run for a long time with minimal fans or cooling.
Is there a performance difference? You bet there is. Core M and Core i-Y CPUs have never been as performance-oriented as even the low-voltage Core i5 and i7 U-series chips found in most mainstream slim laptops. They can, however, offer extra power on an as-needed basis thanks to some dynamic power throttling, boosting performance then easing off to keep internal temperatures in check.
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